1. Field of the Invention
The present invention relates to a temperature control apparatus for a fuser unit, a fan speed control apparatus for a carrier vapor processing unit, for use in an image forming apparatus, and a control method and an image forming apparatus using the same. More particularly, the present invention relates to a temperature control apparatus and a fan speed control apparatus, one for controlling a fuser temperature of a fuser unit, and the other for controlling the rotating speed of the carrier vapor processing unit in accordance with the toner coverage of the data.
2. Description of the Related Art
Generally, an image forming apparatus such as a laser beam printer (LBP), a photocopier and a facsimile, uses an electrophotographic printing method. The electrophotographic printing includes several consecutive processes, which include electrification, light exposure, development, image transfer and fusing.
FIG. 1 shows an engine mechanism of a general LBP as one example of the wet-type image forming apparatus, which adopts the electrophotographic printing method. A sheet of paper for printing is picked up by a pickup roller 108, fed along a paper conveyance path 130, printed and discharged out. The printing process will be described in detail below.
A photosensitive drum 100 is electrified by a charger 101 and therefore, electric potentials are evenly formed over the surface of the photosensitive drum 100. As the surface of the photosensitive drum 100 is exposed to a laser scanner unit (LSU) (not shown), an electrostatic latent image is formed thereon. The electrostatic latent image of the photosensitive drum 100 is then developed by a developer such as a toner which is supplied from a developer unit 106 including a developing roller 106a and a feeding roller 106b, into a visible image. The toner on the photosensitive drum 100 is then transferred onto a sheet of paper, which is fed from a paper cassette 109 by a transfer unit 102. The toner is fixed onto the paper by a fuser unit 303 which includes a heating roller 301 and a pressure roller 302. After the image fusing, the printed paper is discharged out.
The carrier vapor processing unit 400 operates to treat the carrier vapor (v) generated from the fusing unit 300 into a harmless substance.
In an image forming apparatus having the LBP as described above, the inner structure of the heating roller 301 of the fusing unit 300 is in a tubular form, and a heater lamp for generating heat is disposed inside the tubular heating roller 301. For the optimum fusing operation, the fusing unit 300 needs to maintain a uniform and appropriate temperature with the minimum electric power.
The carrier vapor processing unit 400 is additionally provided with a blower which forcibly blows the carrier vapor (v) from the fusing unit 300. Again, it is preferable that the blower generates an appropriate degree of airflow to maintain the proper temperature while using the minimum amount of electrical power.
Many efforts were made on the improvement of the fusing temperature control apparatus. For example, U.S. Pat. No. 5,109,255 entitled “Temperature control system” discloses a temperature control system for use in an electrophotograhic image forming apparatus, which is capable of maintaining the temperature of the fuser at a constant temperature during the printing, and maintaining the temperature of the fuser at a lower degree during non-printing operation.
U.S. Pat. No. 6,011,938 entitled “Fixing device in image forming device” discloses an image forming apparatus, which can maintain the fusing temperature to lower than an initial temperature to prevent overheating, when the fusing operation is continuously performed. U.S. Pat. No. 5,742,865 entitled “Apparatus for controlling temperature of fixing device by increasing the temperature for each sheet of a continuous fixing operation” discloses a temperature controlling apparatus, which controls the temperature for a fusing operation in accordance with the dimensions such as thickness and width of the printing paper.
U.S. Pat. No. 6,148,163 entitled “Control speed and fuser temperature based upon monochromatic or full-color printing” determines whether the image data is color or monochromatic data, and maintains the fuser temperature at a higher temperature when the image data is monochromatic.
U.S. Patent Publication US 20020146256 entitled “Fixing device, method for temperature control of the same, and method for manufacturing rollers of the same” controls the temperature of the heating roller of the fusing device to rapidly reach a predetermined temperature. The entire disclosures of the above-mentioned U.S patents and publication are incorporated herein by reference.
Conventionally, a fuser temperature controlling apparatus and a carrier vapor apparatus do not take the amount of image data into account, and it is inefficient in terms of power consumption. Therefore, a fuser temperature controlling apparatus and a carrier vapor processing apparatus for use in an image forming apparatus, which provide efficient power consumption, is required.